After catching the first available flight home, Ms. Vassar arrived at UMass Memorial Medical Center — University Campus to find her daughter on life support in intensive care.

“I told her Mommy is here. I was not going anywhere. Please talk to me. Please come back out of those machines, Michelle,” Ms. Vassar said.

“I prayed over her. I spoke to her. I begged her to wake up,” she recalled.

Ms. Diaz never regained consciousness.

“On August 30, I had to make the worst decision of my life. My daughter was taken off life support,” Ms. Vassar told the court.

Her recollections were part of an impact statement read in Worcester Superior Court yesterday morning at the sentencing of Donovan K. Smith, the 20 year-old Worcester man convicted Tuesday of first-degree murder and attempted armed robbery in the fatal shooting.

Judge John S. McCann sentenced Mr. Smith to the mandatory life term without parole on the murder charge and to a concurrent prison sentence of 4 to 5 years on the attempted armed robbery charge. The concurrent sentence was recommended by Assistant District Attorney Michael D. McHugh, who prosecuted the case with the assistance of Assistant District Attorney Susan Oftring.

Mr. Smith, formerly of 23 Jefferson St., was found guilty of shooting Ms. Diaz in the neck with a .380-caliber semiautomatic handgun during a failed attempt to rob her of money and marijuana. The victim was shot while sitting behind the wheel of her parked car on Fairfax Road in the Vernon Hill section of the city.

Mr. Smith was one of five people charged in connection with the killing. Three of his co-defendants testified against him under cooperation agreements with the prosecution. His older brother, Marcus Young, is awaiting trial on murder and accessory charges in the case.

Had she learned her daughter was selling drugs, she would have been the first to call the police on her, Ms. Vassar testified at Mr. Smith’s trial.

Yesterday, she spoke of the Michelle Diaz she knew, an integral part of their close-knit family who aspired to be a nurse and worked two part-time jobs while attending Worcester State University.

“She was a role model to her siblings. She would give money to the homeless on the street. She had a lot of goals,” Ms. Vassar said.

“She had a bright smile that would light up a room,” said Ms. Diaz’s sister, Shanice Vassar, who referred to Mr. Smith as “a coward” who committed a senseless and “brutal” crime.

“She had many friends, guys and girls of all ethnicities,” the victim’s sister said.

District Attorney Joseph D. Early Jr. was in court for the sentencing.

“I’m just real proud of our prosecution team and the work done by the Worcester Police Department,” Mr. Early later said.

“This is a verdict that we earned through a lot of hard work and perseverance. What happened today we hope will bring the family some closure with regards to the loss of their loved one,” he said.